This present invention relates to a device and method for reliably improving the heat distribution of immersion tubes for heating chemical substances having critical physical breakdown temperatures. The invention is described in the atmosphere of heater-treaters used for degassing, heating and dehydrating condensable petroleum based oils.
The typical heater-treater currently is a large horizontal or vertical positioned vessel utilizing a continuous tube heater extending between a single burner and an exhaust. This heater heats the oil within the vessel to a sufficient temperature so as to process the oil, separating free gasses, water, suspended solids (sand, etc.) and other foreign matter from the oil during the heating and subsequent physical processing of the oil. The products of combustion from the burner are confined within the tube with the tube transferring the heat thereof to the surrounding oil. This typical heater is serviceable. Unfortunately, however, there normally is a poor distribution of burner heat within the tube; since a single burner is used, it is impossible to control the temperature uniformity of the tube throughout its length. The burner is therefore operated with little concern for the maximum temperature at any location of the tube or the temperature distribution between longitudinal areas of the tube, significantly shortening the service life of the tube (due to thermal stress) and in addition physically damaging at least some percentage of the treated oil (due to operating close to the maximum stable temperature of the oil, causing coking, and/or altering the chemical structure of part of the oil--causing degradation of the service life of the oil)and also the heater tube (the buildup of physical deposits of carbon, coke et al on the outside surface of the tube reduce the boundary layer heat transfer efficiency--in effect insulating the tube from the oil--causing hot spots in the tube). This type of burner operation is also fuel inefficient. Given the current costs of fuel, this adds a measure of cost to the heat transfer process.